Fluid operated switch



July 4, '1939. M. KATCHER 2,164,821

FLUID OPERATED SWITCH Filed July '23, 1937 INVENTOR orris Kutcher l ATTORN Patented July 4, 1939 UNITED STATES PATENT OFFICE 6Claim8.

This invention relates to iluid operated switches and more particularly to switches of this character adapted for installation in uid pressure brake systems for motor vehicles, for completing 5 a circuit to a stop light when the brakes are applied.

Objects of the invention are to simplify and improve the construction and operation of switches of this character, to render them inexpensive l to manufacture, convenient to install and not likely to get out of order.

Other objects and advantages will become apparent upon a further study of the description and drawing, in which:

Fig. l is a section through the switch with the idiiaphragm and contact spring in normal posi- Fig. 2'is a section through the switch with the diaphragm and contact spring shown flexed as V20 when fluid pressure -is applied.

Fig. 3 is a top plan view of Fig. 1.

Fig. 4 is a top plan view of the contact spring shown by itself, and

Fig. 5 is a section taken along the line 5-5 2l of Fig. 4.

The switch comprises a block or body member 6 of an insulating material such as a phenol condensation product. Member 6 is a set in a cuplike 'casing having a base portion 8 and an annular I0 flange or wall portion 1. A central boss 9 is provided for the base portion 8 and is threaded for connection into a uid pressure system such as a hydraulic brake system A passage III is provided in boss 9 so that the pressure' of a pressure 8l system may be applied to the interior of the casare drilled and tapped to receive screws I3 and 40 thus aiIord convenient connection for leads AIl of a stop light or other alarm circuit. The lower ends of terminals II and I2 are exposed through the bottom surface of body member 6. 'I'he bottom of terminal I2 extends farther below said surface than the bottom of terminal II.

Between body member i and base portion 8 is pinched at its edges, a rubber diaphragm I5, with a fish paper washer IB on top of it. Body member 6 is held tight down upon base portion 8, by

50 lip I1 which is pressed over from wall portion 1.

The inner surface of block 6 has its central portion at a higher elevation than its marginal portion.

A plate spring, denoted in its entirely by nu- IIIi meral I8, has a mbstantially semi-cylindrical raised portion I 9 with an opening 20 in its top. Terminal II has its lower end inserted through opening 20, and its edges peened over to grip the underside of portion I9, a metal washer 2| being inserted between. Flanges 22 are turned up at diametrically opposite edges of spring I8 to act as spacers for holding down said edges of the spring when the switch is assembled. Pressure upward against the spring causes flanges 22 to react against the bottomvof body member 6. Normally, with no iluid pressure applied to the underside of diaphragm I5, spring I8 is away from the bottom of terminal I2. However, when uid pressure is transmitted through passage I0 against the underside of diaphragm I5, the latter presses up upon spring I8, bowing the latter up against the bottom of terminal I2. Spring I8, being iixed to terminal II, the application of huid pressure to the underside of diaphragm I5, closes the circuit between terminals II and I2.`

The terms used in the claims relating to posiltion such as base, top, upper, etc., are intended to be relative only.

I claim:

l. A fluid operated switch comprising a casing having a chamber formed therein, the bottom portion of the casing having a passage through it leading into said chamber, a flexible diaphragm in said chamber extending across and sealing said passage, a. pair of spaced terminals insulatively mounted in the upper portion of the casing having their inner ends exposed to the interior of the casing, and a metallic plate spring in the chamber above said diaphragm having a. raised portion at one end in contact with the iirst of said terminals while the opposite end of the spring is normally out of contact with the second of said terminals, the opposite sides of the spring intermediate said ends being held down at all times by portions of the casing against substantial motion towards said second terminal, said diaphragm bowing up the spring between said sides against said second terminal when pressure is sent through said passage.

2. A fluid operated switch comprising a casing having a chamber formed therein, the bottom portion of the casing having a passage through it leading into said chamber, a flexible diaphragm in said chamber extending across and sealing said passage, a pair of spaced terminals insulatively mounted in the upper portion of the casing having their inner ends exposed to the interior of the casing, and a metallic plate sprmg, in the chamber above said diaphragm, having a raised portion at its end below the first of said terminals,

through said passage, said spring thereby closingV the circuit between the terminals.

3. A uid operated Vswitch comprising a casing having a chamber formed therein, the bottom portion of the casing having a passage through it leading into said chamber, a flexible diaphragm in said chamber extending across and sealing said passage, a pair of spaced terminals insulatively mounted in the upper portion of the casing having their inner ends exposed to the interior of the chamber, and a metallic plate spring in the chamber above the diaphragm having a raised semi-cylindrical portion atits end below the iirst of said terminals, the top of said semi-cylindrical portion being fastened to said irst terminal, the opposite end of said spring being normally at a distance from the second of said terminals, opposite sides of the spring, intermediate said ends, being held down at all times by portions of the casing against substantial motion upward, said diaphragm bowing up the spring between said held down sides, causing, thereby, the spring to contact said second terminal when pressure is sent through said passage.

4. A fluid operated switch comprising a casing with a cover portion, said casing having a chamber formed therein closed by said coverportion, the bottom portion of the casing having a passage through it leading into said chamber, a exible diaphragm in said chamber extending across and sealing said passage, a pair of spaced terminals insulatively mounted in the upper portion of the casing having their inner ends proecting into said chamber, the first of said terminals projecting into said chamber a substantially 'greater distance than the second, and a metallicV plate spring, in the chamber above said dia-l phragm, having a raised portion at one end occupying substantially the central portion thereof, said end being fixed to the second of said terminals, the opposite end of the spring being normally at a distance below said rst terminal, the sides of the spring intermediate said ends being bent upward engaging the underside of the cover portion holding said spring down adjacent said sides, said diaphragm bowing up the spring between said sides against said first terminal when pressure is sent through said passage.

5. A uidpressure operated switch comprising a casing having a chamber formed therein, the bottom portion of the casing having a passage through it leading into said chamber, a flexible diaphragm in said chamber extending across and sealing said passage, a pair of spaced terminals insulatively mounted in the upper portion of the casing having their inner ends exposed to the interior of the chamber, and a metallic spring substantially in the form of a disc having one end engaging the rst of said terminals, the opposite end of the disc being normally at a distance below the second terminal, the sides of the disc intermediate said ends being bent upward, the bent up portions being held down by the casing against upward motion, holding said disc down adjacent said sides, the disc at said sides extending substantially across the width of the chamber, said diaphragm bowing up the disc between said held down sides against said second terminal when pressure is sent through said passage.

6. A iluid pressure operated switch comprising a casing having a chamber formed therein, the bottom portion of the casing having a passage through it leading into said chamber, a iiexible diaphragm in saidchamber extending across and sealing said passage, a pair of spaced terminals insulatively mounted vin the `upper portion of the casing having their inner ends exposed to the interio'r .of the chamber, and a metallic plate.

spring in the chamber above said diaphragm having one end engaging the first of said terminals, the opposite end of thespring being normally at a distance below the second of said terminalsthe opposite sides of the spring intermediate said ends being held 'down against upward motion by reacting against the casing, said diaphragm bowing up the spring between its held Adown sides, against the second of said terminals when pressure is sent through said passage.

MORRIS KATCHER. 

